MOTOTRBO GPS in a nutshell

Radios with model names ending with a 1 (e.g. DP3601 or DM4401) have an integrated GPS receiver. This receiver is purely a reporting tool (i.e. the radio user cannot see where they are like on a traditional GPS unit). MOTOTRBO radios uses a protocol called LRRP (Location Request Response Protocol) to send GPS updates to a predefined Radio ID (i.e. destination address). LRRP uses triggers to schedule GPS updates: these include GPIO event; delta time; delta distance or immediate.

GPS updates are processed by a location server (effectively a standard PC with a tracking application on it). The operator (person) sends a location request to a radio via the tracking application installed on the PC. The server is connected to a Control Station, which is used to send the request. This location request contains information about the triggers: for example, send GPS data every ten minutes or every 1 kilometer, whichever happens first (this is chosen by the operator via the location application).

The Control Station can be any MOTOTRBO radio - mobile or portable. The radio is connected to the server via a standard USB cable. This radio would be programmed to monitor the radio channel or system.

[Edit 10.09.13] Note that as of system release 2.2, control stations are not required and certain Application Partner products are able to access the radio network directly via the repeaters. This uses the NAI feature (Network Application Interface).

The radio stores this location request and when one of the triggers have been reached, the radio sends a GPS packet (takes less than 600ms). The GPS is sent as UDP/IP data over the air, to the predefined Radio ID. The radio which receives this packet forwards this to the PC, which displays the radio location on a map. There are different ways to handle the GPS update, in terms of channels and coordination.

Another MOTOTRBO feature which works hand-in-hand with GPS is ARS (Automatic Registration Service). This causes the radio to send a registration packet every time the user switches on or (optionaly) changes site. ARS is also supported in non-GPS models.

The map and location request management, is part of one of many possible applications from several possible Motorola Application Partners.

More details on how GPS is handled in MOTOTRBO can be found in the MOTOTRBO System Planner. More information on which Motorola Application Partners produce GPS tracking applications can be found in the Application Partner Catalogue. Both of these documents are available to Channel Partners, for download from Motorola Online. The Application Partner catalogue is available for download on my Blog or on Motorola's website.

If you dont have access to Motorola Online, you can request a copy of the latest MOTOTRBO System Planner from your Motorola Supplier. A summarised version of the MOTOTRBO Application Partner Catalogue is available on the web at http://bit.ly/RzwoDd.

31 comments:

  1. Hi Wayne!
    I discovered that in my conditions (DP3601 radio placed at a window of house) the accuracy of GPS data is very poor. Constant error is about 50m and sometimes I observed surges of GPS marks on distance of 300m. Could you tell me is this normal for Motorola radios and what are the reasons of such problem?

    ReplyDelete
    Replies
    1. What you are seeing is quite normal for *all* GPS receivers. The most likely reason for the error you are seeing is the fact that the radio was switched on then placed next to a window with no clear view of the sky. Try powering up the radio outside with a full view of the sky and leave it for about 2-3 minutes before putting it next to the window.

      You are also possibly comparing the performance with a car navigation system (e.g. TomTom; Garmin et al.) - these devices use snap to roadway which places the car icon on the nearest road giving the appearance of excellent accuracy.

      Chapter 2.4.1 of this publication http://www.gmat.unsw.edu.au/snap/gps/gps_survey/principles_gps.htm is also worth reading.

      Delete
    2. Thank you Wayne.
      And one more question is what does it mean "The radio stores this location request and when one of the triggers have been reached, the radio sends a GPS packet"? I've never heard about GPS triggers in Mototrbo radios. Does this mean that control station sends GPS request only once till radio is registered and this one sends its own position information by itself in defined intervals of time without requests?

      Delete
    3. Correct, the server (control station) only needs to send a single request containing the trigger information (time or distance or both). The server could optionally only do this once the radio has powered up and registered (ARS).

      Optionally, the dispatch operator could request an immediate update in which case the radio would respond as soon as possible with coordinates - even if the time/distance limit hasn't been reached.

      Delete
  2. Does using GPS on MotoTRBO radios require specific antennas? in case of portable radios i heard normal antennas are acting as gps antennas too, but i'm not sure if mobile radios are fine with their own antennas? are they require one antenna for sending radio waves and one for receiving gps signals? or maybe they have built in gps signals like gps devices?

    ReplyDelete
    Replies
    1. On the DP3000 series the GPS antenna was part of the radio antenna so a special antenna was required.
      On the DP4000 series (incl. DP3441) the GPS antenna is in the radio.

      On all MOTOTRBO mobiles however you need a separate GPS antenna and coax cable.

      Delete
    2. once again you were helpful and yet very fast. you simply are the best. Thanks

      Delete
  3. Hello,

    I have a question about GPS system. In my situation, I have DM 3601 with GPS in my car and i have DM 4600 like control station on my PC with application.

    But I notice that it is the DM3601 in my vehicle that sends its GPS data about 15 -20 secondes) to the control station, not the other way around. Is this normal ?

    Is not the DM4600 base to ask for the GPS position of mobile radios ?

    Thanks

    Anthony

    ReplyDelete
    Replies
    1. What you are seeing is normal. The base will only need to send one request to get continious updates.

      Delete
    2. Hello,

      Thank you.

      Delete
  4. Hello, Im using mototrbo XPR6550 with GPS. Im trying to get location data using LRRP. we are able to send request.But not able to Trigger-Location-Answer from XPR6550. Is there any specific setting needs to be done

    ReplyDelete
    Replies
    1. Are you an application developer?

      Delete
    2. Yes..we as a team enhancing feature by using mototrbo devices. currently im stuck with LRRP request response

      Delete
    3. If you are an application developer, why don't you submit this question on MSI Github? You will have got those details when you signed the ADK license.

      Other than that, I can't really help you as I'm not so familiar with the ADK.

      Delete
    4. Sorry, MSI GitLab I meant.

      Delete
  5. Hello. I'm using Motorola DM4600 as master station and couple of DP4601 handsets. I would like to collect from the DM4600 the GPS data of all DP4601 and store them in my own Database in order to use them on google map. how can I extract GPS data from DM4600 without any software dispatcher ?

    ReplyDelete
    Replies
    1. Location updates can only be seen and managed via a PC based application. There are many applications to choose from - see https://www.motorolasolutions.com/en_xu/application-catalog.html.

      Delete
  6. Hi, Is there any way to have GPS on DP4801 off unless a trigger is sent? We don't want GPS on the whole time as it drains the batteries, but if they ever get lost would be useful to switch on GPS and get location with a manual trigger. Is this possible?

    ReplyDelete
    Replies
    1. The GPS receiver needs to be turned on to get a fix but you can have the radio only send it's location (once) when requested to do so by the dispatch console.
      The receiver itself doesn't consume much battery power, it's transmitting the updates that does.

      Delete
  7. Hi Wayne,

    Thanks again for all your support on this blog.

    Another quick question: We have 4 radios that are GPS enabled using slot 2 as GPS revert channel. We only use slot 2 occasionally for voice so aren't so concerned about that, the issue is how often can we get the radios to send location without a risk of missing out on voice over slot 1 (while it is using revert ch 2).

    Thanks,
    Stuart

    ReplyDelete
    Replies
    1. It depends on how busy slot 1 is because a radio will not send an update while in a call. If slot 1 is quiet, you should get about 120 updates per radio per hour.

      The calculator says that with four radios, doing 3 voice calls per user per hour and 2 text messages per user per hour, you should be able to support 60 GPS updates per user per hour.

      Delete
    2. Thanks that's useful. We actually have 40ish radios but only 4 have GPS enabled. Slot 1 is usually silent apart from when there is an incident then there is lots of voice traffic, so all GPS will probably be suspended then in anycase.

      Delete
  8. We have GPS on a DM4601 and it works fine close to the repeater. As soon as it goes a bit further away it is unable to send the location and send / receive text messages even though the voice is still crystal clear (both Rx & Tx). Could it be that there is enough reception for voice but not enough for data? Or could there be a setting that makes data less likely to send when in limited range?

    ReplyDelete
  9. Hi Wayne,

    Love your blog. It has helped me a lot; especially on the radio management topic.


    I was wondering if it is possible get live GPS data straight from the DGM8500 accessory connector, to a connected device.

    ReplyDelete
    Replies
    1. In theory that is possible but you would need to know some details about the XCMP protocol used on these radios. See bit.ly/2jAGTRd.

      Delete
  10. When GPS in handhelds is needed, I strongly recommend going for the e series radio. The move from a DP4801 to a DP4801e made GPS usable - when the DP4801 often did not get a fix on a 500m walk and required to stand still for minutes with the radio held in the hand or put on a fence, the DP4801e usually gets a fix while being in the pocket within minutes. And when it got a fix outdoor it even can carry it into a train and track on for hundreds of kilometers. The e series is a real winner!!

    ReplyDelete
    Replies
    1. The DP4801e uses a UBLOX chip for GPS whereas the DP4801 used a NaviLink chip from TI. The UBLOX is newer and probably has better performance specifications.

      The RF performance will be better too - particularly on RX.

      Delete
    2. Yes, while the DP4801 by means of RX already outperformed all Hytera handhelds, the DP4801e is even better. I thought, well, those 50nV of higher sensitivity can't be a big deal, but they are a big deal! In a fringe coverage area both DMR and FM changed from broken coverage to almost 100% clear coverage. On a radio tester I get first intelligible FM audio around 0.05 or 0.06 µV, this is absolutely crazy. And when watching the radios RSSI display, it starts decoding DMR below -126dBm - the RSSI is calibrated quite well, so the figures are real.

      A few ham radio users also noticed these days that they can have undisturbed conversations with their newly purchased DP4801e radios in places where the PD785 handhelds just bonked at them. And we all are using the stubby antenna.

      Delete
  11. Hi Wayne, Is there any way to send GPS coordinates from one GPS enabled radio to another without using a third party application?

    ReplyDelete
    Replies
    1. No there isn’t. Might be possible via an option board - not sure who does this though.

      Delete

Powered by Blogger.